Three NCSU scientists working in fields in which protein-protein or protein-nucleic acids interactions are a primary component, propose to purchase a spectropolarimeter capable of steady-state and stopped-flow circular dichroism (CD) studies. The instrument, manufactured by Applied Photophysics, is intended as a replacement and upgrade for an existing and outdated Jasco CD purchased in 1989. The existing instrument remains the only CD instrument on the NCSU campus and is used heavily by several faculty across the campus. However, it becomes increasingly difficult to maintain the instrument in working condition in order to acquire adequate data. The existing instrument will not provide reliable data below 200 nm, the temperature control is poor, the software and computer are antiquated, and it does not have stopped-flow or titration capabilities. In the past three years, the instrument has required several thousand dollars in repair costs to remain functional. The proposed instrument will enable the study of protein and nucleic acid conformations and provide information on protein and/or nucleic acid stability as well as protein folding mechanisms. Measurements of binding profiles will allow the determination of binding constants and stoichiometries, thermal dependence to circular dichroism parameters will be obtained, and kinetic reactions will be measured. The instrument will facilitate the current experimental approaches of the investigators which include NMR spectroscopy, fluorescence spectroscopy, X-ray crystallography, differential scanning and isothermal titration calorimetry, circular dichroism, mass spectrometry, and other biochemical and biophysical techniques. The steady-state and stopped-flow spectropolarimeter will complement NIH funded structural and functional studies focused on understanding the folding and assembly of caspases, transition state regulator proteins involved in bacterial response and protection, and characterization of modified nucleoside contributions to RNA and to RNA:peptide and RNA:metal interactions. [unreadable] [unreadable]